The aims of this study were to investigate the detection of cervical lymph node metastases of head and neck cancer by positron emission tomographic (PET) imaging with fluorine-18 fluorodeoxyglucose (FDG) and to perform a prospective comparison with computed tomography (CT), magnetic resonance imaging (MRI), sonographic and histopathological findings. Sixty patients with histologically proven squamous cell carcinoma were studied by PET imaging before surgery. Preoperative endoscopy (including biopsy), CT, MRI and sonography of the cervical region were performed in all patients within 2 weeks preceding 18F-FDG whole-body PET. FDG PET images were analysed visually and quantitatively for objective assessment of regional tracer uptake. Histopathology of the resected neck specimens revealed a total of 1284 lymph nodes, 117 of which showed metastatic involvement. Based on histopathological findings, FDG PET correctly identified lymph node metastases with a sensitivity of 90% and a specificity of 94% (P<10–6). CT and MRI visualized histologically proven lymph node metastases with a sensitivity of 82% (specificity 85%) and 80% (specificity 79%), respectively (P<10–6). Sonography revealed a sensitivity of 72% (P<10–6). The comparison of 18F-FDG PET with conventional imaging modalities demonstrated statistically significant correlations (PET vs CT, P = 0.017; PET vs MRI, P = 0.012; PET vs sonography, P = 0.0001). Quantitative analysis of FDG uptake in lymph node metastases using body weight-based standardized uptake values (SUVBW) showed no significant correlation between FDG uptake (3.7±2.0) and histological grading of tumour-involved lymph nodes (P = 0.9). Interestingly, benign lymph nodes had increased FDG uptake as a result of inflammatory reactions (SUVBW-range: 2–15.8). This prospective, histopathologically controlled study confirms FDG PET as the procedure with the highest sensitivity and specificity for detecting lymph node metastases of head and neck cancer and has become a routine method in our University Medical Center. Furthermore, the optimal diagnostic modality may be a fusion image showing the increased metabolism of the tumour and the anatomical localization.

Prospective comparison of 18F-FDG PET with conventional imaging modalities (CT, MRI, US) in lymph node staging of head and neck cancer

Purpose : An accurate and rational nasopharyngeal carcinoma (NPC) stage based on images is proposed. Methods and Materials : Four hundred and twenty-one cases of NPC, treated in the Cancer Hospital, Sun Yat-sen University of Medical Sciences (SUMS), with computed tomography scanning before initial radiotherapy, are analyzed. Important prognostic factors that form the basis of the new staging system are screened out by means of Cox model and clinical experiences. Survival curves of various kinds of T and N stages are compared by computer simulation. A new staging system is proposed by studying the traditional staging systems such as the AJC, UICC, Ho's and Changsha systems. Results : According to the new staging criteria, the 5-year survival rates for Stages I–IV are 89.7%, 75.9%, 51.3%, and 22.2%, respectively. Conclusion : This new clinical staging for NPC based on a large amount of cases multivariate analysis is satisfactory and widely used in China.

A new staging system for nasopharyngeal carcinoma in china

MRI differentiation of recurrent nasopharyngeal carcinoma from postradiation fibrosis.

MRI has been used increasingly in the evaluation of nasopharyngeal carcinoma (NPC) because of its good tissue contrast and multiplanar capacity. Although there are some controversies in assessing skull base invasion and cervical metastatic adenopathy, recent reports demonstrate that MRI is currently better than or as good as CT in defining the extent of NPC. During follow-up of patients with NPC after radiotherapy, MRI is also more effective than CT in demonstrating tumor recurrence and in detecting postradiation complications. However, the difficulty of using MRI to detect early mucosal recurrence and to differentiate postradiation tissue changes from local tumor recurrence should be recognized. This paper reviews the literature regarding MRI of NPC related to radiotherapy, with special emphasis on treatment planning, recurrence assessment, and complication detection.

Invited. MRI of nasopharyngeal carcinoma with emphasis on relationship to radiotherapy

Two hundred and seventeen consecutive patients affected by nasopharyngeal carcinoma (NPC) were treated with radiotherapy alone, with curative intent, from 1970 to 1985 at the Radiotherapy Unit of the University and Hospital of Florence. A group (A) of 111 patients staged with conventional clinical and radiological method was compared to a second group (B) of 106 patients who underwent CT staging before treatment. Group B showed better 5-year NED survival and local control; only the differences in local control were significant (p < 0.01). As to primary control statistically significant differences were observed in T2 and T4 cases. We feel that CT could have contributed to the improvement, probably through a more reliable display of the primary extent and a more adequately planned radiotherapeutic treatment. With CT staging we could not increase our skills in prognostically separating stages according to UICC criteria (1978); in Group B only T2 patients presented significant differences in primary control when compared to T3 and T4 patients. However, a multivariate analysis of prognostic factors showed that nodal involvement, primarily, and histology, secondarily, were the most important factors, T stage showed a minor influence on prognosis.

Peihong Wu

Papers

Computed tomography in the management of nasopharyngeal carcinoma.